There are so many aspects of copyright to think about when you are writing a book. Look at this:
"The case of writer Barbara Chase-Riboud, for example, shows that if a story is completely made up, it's easier to protect than if it's based on fact. She successfully sued a playwright for copying her treatment of the story of Sally Hemings, the mistress of Thomas Jefferson, as a play because at the time of the lawsuit it wasn't accepted historical fact that Jefferson had in fact slept with Sally Hemings." READ MORE by San Francisco Chronicle writer, Adair Lara.